Diabetic nephropathy is a frequent complication of diabetes mellitus. It is generally believed that thickening of the glomerular basement membranes is responsible for kidney damage.
Glycoproteins perform a decisive role in the structure of basement membranes, the carbohydrate portion of such glycoproteins being linked to the apoprotein principally through asparagine and hydroxylysine residues. It is known that in diabetics the amount of hydroxyproline, hydroxylysine and saccharide part of the glycoproteins in the basement membranes of the kidney is increased as compared with normal healthy subjects (see Diabetes 25, 909-913 [1976]).